Hair-spring collet for watches.



.l. FREISTADTER.

HAIR SPRING 0 LL T FOR W TCHES.

APPLICATWN D OCT- 7, 1914.

1,136,950. I I Patented Apr. 27,1915.

To all whom it o balance staifs, and is embodied 1n acollet which'is a continuoustring" instead ofbeing J'Acq rnnrs'rnnrnn, or nmm, mnssncnus'nrr s. I

- A11zisrn1necoL nTron wn'rcnns'. r

' Application filed wa 7, 19 4. semi No. 865, 74. 5 1

Be it, known that I, J ACOB sme ma a citizen of the United States,,.and resident of Waltham," in the county of Middlesex and State of Massachusetts, have invented certtain new and useful Improvementsin, Hair- Spring Collets for" Watches, of which the h following is a specification,

This invention'relates to colle tsi employed 7 for connecting watch balance hair springs to l a ring the continuityof which is entirely in:

terrupted at one :side and is variable in diameter, my improved collet belng therefore perfectlypoised because its weight'is,

uniformly distributed and is not decreased at one side as would be the case if its continuity were interrupted at one'side.

The collet ofmyinventmn, while consti-' so that said bore isadaptedto closely fit a usual hair spring, said-spring being "secured tional fit thereon. a o p I attain the objects of my invention by the construction which I: will now proceed to p I I I Itwillbe seen that while the continuity of the collet is not interrupted and the bore I thereof is-not capable of expanding and con-I, 7

staff portion which difiersslightly in form from the normal form of the bore.- "For-example, if the bore-is cylindrical andxthe' staff is slightly tapering the bore will conform accurately to the staff and have a close fricdescribe 1 Of the accompanyingdrawlngsforming a part of'thisspecification: Figure represents an edge view of a collet embodylng my invention;Fig. 2 represents a side view of the fsame; Fig, 3 represents a section on line '3-'3'of Fig. 2; Fig.4 represents a 830131011 on line 4-4 of Fig. 1;,Fig. 5 represents asection on line5 +5 of Fig. '1'; Fig. l6' represents a View similar to Fig, 3, showing the collet engaged withabalance fstafi.

The collet ,is shown on an enlarged scale -in all the figures, p

' The same reference characters indicate; the

same. or "similar parts in 'all the views.

In making my improvedcollet I form a bore for thereception of' 'one end of the in in any suitable wayl In 1 one sldeof the ring I form a slot 15 which I 15 extends 'partly,;but not entirely, to the 0pposite side ofthe ring and intersects the bore 13, the continuity of the slot 15 being inter-Q ew sfwtA5 mamas. 27, 1915. f

rupted by the bore; In other words, theslOt borer" In the opposite side of the ring, I form two, slots 16- which extend entirely '15 ismade'in' two partslalined with each other-and separatedfrom-eachotherby the across one side of the'ring and partly,flbut not entlrely, to the side'injwhich'the twoe;v

part, slot 15, is formed,the slots 16 partly, I

intersecting the bore 13, as shown by Figs. 3 and! The slots 16 are at opposite sides of "the two-part slot 15 and-are separated therefrom,-as shown. a v 1 All watches, including so-called precision or adjusted watches, show in somedegree a position'error'when testedby running them ,ln different positions, and this error has heretofore been'due in part to the fact that the hair spring collet is not w accurately:

poised, or is non-'polsed, because its continuity isentirely interrupted at one side to give it the desired flexibility andjadjustability,

the collet being in effect a cut ring which is lightest at its out side. This lack of poise 1 Y, 1n the collet helps to 'cause'afposition error in the rate of watches and -other-portablew time pieces. I g

Since the collet of my, invention is' not lighteratany' point on its perimeter than at I a diametricallyopposite point, it follows I that the collet is always in poisevand is not a a factor in causing a position error;

tractingllike the bore of a collet which is entirely interrupted or cut at one side, the I end to end tothe' collet-engaging portion 18 bore has a skeleton form which renders it p I "suitably flexible or: self-conforming from of a balance staff, so that incase the'bore 13 is cylindricalzind .thestaff .portion 18 is stantially cylindricalstafi, a I t V I believe myself, to "bet he first to provide a poised continuous hair spring collet having a staff-receiving borethe wall of which I entirely surrounds the collet-engaging por tion of a balance stall and is self-conforming from end to end to the collet engaging'portion of a balance stafi. I do not therefore limit myself to the precise construction.

struction to produce thedescribed results without departing from the spirit of the invention.

Having described my invention, 1 claim:

1. A hair-(spring collet having a staff-receiving bore formed to entirely surround the collet-engaging portion of a balance stafi, whereby the colletis poised, said bore being self-conforming from end to end to said portion.

2; Aliair spring collet haying a staff-re ceiving bore formed to entirely surroundthe collet-engaging portion of a balance staff,

whereby the collet is poised, said bore being or toslight irregularities of'sa'id portion.-

p A poised continuous'hair spring collet. slotted partly across from opposite sides,

said slots intersecting the wallof the staffreceiving bore of the collet', and rendering said wall self-conforming 5 to the collet-engaging'portion of a balance staffi'. 1

In testimony whereofI have 'afliXed my signature, in presenceof two witnesses.

Witnesses I a E. P. 'BRANNE'N, P. W. PEZZETTI;

Copies of this patent may be obtained for five cents each, by'a'ddressing the Commissioner of Patents,

' washingtonfllc.

JACOB- FRE'VIST'ADTER. 

